Development of Global Visual Processing: From the retina to the Perceptive Field;
Reducing the impact of the Crowding phenomenon & Improving Contrast Sensitivity.
In recently published research with the above title, the authors data suggests that the developmental processes at the retina and at visual cortex occur in the same age range.
In other words; The fovea development increases contrast sensitivity (which enables increased Visual Acuity) at the same time that the brain's Visual Perceptive Field improves (which enables reduction in crowding).
These functions typically leap forward at around age 6. This is observed in practice as the age when children are better able to keep place on the whole line when reading a letter chart rather than requiring isolated letters.
Understanding and appreciating crowding serves as the basis for why children’s books have larger print and liberal spacing until age 6, and then each year thereafter progress toward smaller print with tighter spacing, in essence becoming relatively more crowded.
If a child is delayed in either retinal development, cortical development, or the timing/linkage between the two, they will not be ready to read words, least of all small words.
Optometric Vision Therapy helps children who lag in retinal and/or cortical development through the use of many types of sheets or workbooks that progress from larger font and spacing toward smaller font and closer spacing.
Computerized Therapy, such as HTS AmbiNet program that we use here at VisionLink, for this is customizable and auto-pacing to help develop both contrast sensitivity and reduction in crowding with the least stress to the patient.
Bibliography: Development of global visual processing: From the retina to the perceptive field
Doron R, Lev M, Wygnanski-Jaffe T, Moroz I, Polat U (2020) Development of global visual processing: From the retina to the perceptive field.
PLOS ONE 15(8): e0238246. https://doi.org/10.1371/journal.pone.0238246